Searchlight and other projector



Jan. 29, 1924; v 1,482,142

C. A. PARSONS ET AL SEARCHLIGHT AND OTHER PROJECTOR Filed May 10 1920 2Sheets-Sheet I Q lm/en tors:

Charles P64760115 Ebanezar Bennett, B Harry Pom/6 4 5 M w -fi mmmav Jan.29, 1924. 1,482,142

C. A. PARSONS ET AL SEARCHLIGHT AND OTHER PROJECTOR Filed May 10 1920 2Sheets-Sheet 2 Harry Powe.

Patented Jan. 29, 192 4.

UNITED STATES PATENT OFFICE.

CHARLES ALGERNON PARSONS, EBENE'ZER BENNETT, AND HARRY ROWE, OF NEW-CASTLE-UPON-TYNE, ENGLAND; SAID BENNETT AND ROWE ASSIGNORS TO SAIDPARSONS.

SEARC HLIGHT AND OTHER PROJECTOR.

Application filed Kay 10, 1920. Serial no. 330,372.

To all whom it may concm:

Be it known that we, CHARLns AIGEKRNON PARSONS, K. C. B., EBEN'EZERBENNE'I'I, and HARRY Rown, all subjects of the King of 5 Great Britainand Ireland, and residing at Heaton Works, Newcastle-upon-Tyne, in thecounty of Northumberland, England, have invented certain new and usefulImprovements in Searchlight and ()ther Projectors,

of which the following is a specification.

This invention relates to Searchlight and other projectors and has forits object to provide means for keeping the temperature of the mirrorand other parts at a moderate temperature so that increased intensity inthe power of the light can be obtained without damage to the apparatus,with the result that larger currents can be employed producing morepowerful beams of light.

Searchlight reflectors are usually constructed of glass, silvered on theback surface, the silver being protected by copper plating reinforcedeither by sheet lead, varnish or other means, and in some cases re- 26flectors are made of metal plated with silver, gold, palladium or otherhigh reflecting surface.

The factor limiting the intensity of the power of light in suchprojecting apparatus 30 is primarily the temperature which the mirrorcan stand.

The heating of the mirro in a projector arises partly from radiantijieat and partly from general heat generated by the flame of the arcand the combustion of the carbon carried by convection and conduction,and the temperature of the mirror is also affected by the general riseof temperature of the projector caused by radiant and conveyedorconducted heat.

The present invention consists broadly in providing means by which heatother than radiant heat can be drawn off and dissipated so that thetemperature rise of the mirror is minimized.

The invention further consists in providing a water jacket surrounding,or nearly surrounding the arc, and also adapted to shield the body ofthe projector from radiant heat.

The invention further consists in providing in combination with acooling jacket a chimney adapted to draw ofi' the hot gases port.

produced by the are so that they with the air in the rojector.

The invention urther consists in constructing the water jacket in such amanner that it shields the body of the projector from the greater partof the radiant heat of the arc while allowing a cone of lightsufficiently large to pass freely to the mirror.

The invention further consists in the improved means for limiting thetemperature of mirrors in projectors of searchlights and the likehereinafter described.

Referring to the accompanying drawings;

Figure 1 is a front view and Figure 2 a sectional elevation of an arclamp constructed according to the invention, while Figures 3 and 4, 5and 6, 7 and 8, 9 and 10 are detail views showing modifications of thecooling jacket.

In the form of the invention illustrated in Figures 1 and 2, We providea water jacket a preferably made of copper in the form of a saddlesurrounding the are 6 as completely as possible. When the standard lampis used a longitudinal opening below is left to allow assage for thepositive carbon supuitably placed above the water jacket we provide atank or reservoir 0 containing water connected to the water jacket byipes d opening into the tank at different evels e f so that acirculation by the heating of the water takes place through the pipes,water jacket and tank.

In the upper portion of time water jacket do not mix we insert a chimney9 opening almost immediately above the arc and adapted to lead away theflame of the arc and the very hot gases produced by, and in theneighbourhood of the arc, thus preventing these gases from mixing withthe air in the projector band and thereby reducing the temperature ofthemirror. Natural circulation may be sufficient but it may be assisted bya fan of ordinary construction operable in the ordinary manner but notshown as it forms no part of this invention.

The jacket may be constructed in such a manner that it shields the bodyor barrel of the projector from the greater part of the radiant heatwhich would otherwise fall upon it from the arc, only leaving a cone oflight sufficiently large to embrace the mirror and thus only allowingfree passage for the radiant heat which cannot be avoided withoutdiminishing the intensity of the light falling von the mirror. Thus themirror is subjected to very little heating exceptthat which arises fromthe radiant heat emanating from the crater oi the arc.

The jacket may only surround the upper part of the are as alcovedescribed or it may be constructed so as to completely surround the arc.lln the latter case, however, the portion of the jacket which is an;ediately below the arc should be constructed oil a ll form, as shown inFigures 3 and l, or such other form as will avoid the occurrence of asteam look, as otherwise hot particles falling on the thin copper orother material of which the jacket is composed would melt the metal anddestroy the jacket.

The water pipes leading to the acket may be arranged in difierentmanners, for example, in Figures 3 and a, the cooling pipe h may bearranged to open into a sump is arranged at one end of the jacket a andimmediately below the arc, while the hot water outlet pipe Z isconnected at the top of the jacket. liurther, the aperture in the jacketmay he ct any desired form, for instance, the aperture may he ofgradually increasing diameter from the front to the back, as shown atFigures 5 and 6, or other forms of aperture may be adopted, as shown inFigures 7 and'8, and 9 and 10, according to the type of lamp and thedirection in which it is required to throw the beam of light. lln

fact, any suitalole arrangement oil jacketing and piping may be employedto suit special circumstances.

Having now described our invention, what we claim as new and desire tosecure by Letters Patent is l. A lamp including a barrel, an arc withinthe barrel as the source of light, a water jacket for the arc andadapted to intercept the radiant heat from the are, a reservoirsupplying a cooling fluid to said water jacket, and circulation systemincluding an inlet pipe and an outlet pipe extending into the reservoir,the reservoir end of the inlet pipe being at a lower level than that ol?the outlet pipe connecting said water jacket and 2. A lamp including abarrel, an arc withtill in the harrel as the source of light, a waterlln testimony whereof we have signed our names to this specification.

CHARLES ALGERNON PARSONS,

EBENEZER BENNETT. HARRY ROWE.

